Subject: MGA Engine Rebuild Questions
Date: Sunday,January 14,1996 7:45AM
The engine's out and somewhat disassembled. Please go easy on me.
Although I've "assisted" on several American V8 rebuilds this is my first
solo and my first MG.
1) How does one get the 1-5/16 nut off the camshaft? Try to turn it and
the shaft turns. The only thing I can think of is put the block in a car
and take it to someone with an impact wrench. Is there a way to keep the
shaft from turning?
Put your engine on a stand if it isn't already. It will save you lots of
time and their cheap. Keep the sprockets and chain connected to the cam and
crank.. You should have the opil pan off by now. Rotate the engine upside
down on the stand and place a large wrench on what looks like a bracket
inside the crank case. When you rotate the crank you will notice that the
counterweights on the crank will hit the wrench and stop it from rotating.
Now you can work on the cam nut and the crank nut. An impact gun is really
the easy way to do this otherwise you need a 22" breaker bar or a strong
Whoops. I assumed that this was a B engine. Perhaps there is something
similar in the A
2) The head is off and pistons out. These pistons are five ring: four
above and one below the pin. Were these original to the 1600 MGA? The
pictures in my manuals show only four rings above the pin. The number
four con rod is apparently from another engine. DPO must have lost a rod
among other things. Bores look good except for a little scuffing on
number four which is to be expected given the buggered condition of the
corresponding big end bearing. It was actually _loose_. I'll have to
have the machine shop check them. Will they have the required numbers?
I would give it to them yourself. Every time I went to check on my B engine
they kept calling it a midget engine even though it says 1800 right in the
side. They may need to turn down your crank if the journal was damaged. Have
them polish it. They will tel you whay size bearings to get.
3) After I get the crank and cam out I guess my next step is to have the
shop find out if the crank is still usable. How do I tell if the cam is
OK? Take it to the shop also? What do I do about the cam bearings?
Should I have the shop check the pistons? What else needs to go to them?
When you take the engine in and have all of this work done you should pull
all the water plugs and have the engine hot tanked to remove rust deposits
and other goo. This process will remove your cam bearings. Have them press
new ones in. If you have a micrometer you can measure the lobes on your cam
and compare them to specs. An easy way to tell though is to check the lobes
for scuffing or abnormal wear, you can just take it to the shop and they'll
check it for you. When they check the bores on your engine they will tell
you if you need to purchase oversized pistons and rings. If you have ovaling
or scoring you will have to go .010 over. In worse cases .030 oversized.
4) What are the things that should definitely be replaced? Like con rod
bolts and ???
Oil pump, water pump, all gaskets, check the oil pressure relief spring, If
you replace the cam, buy new tapets, timing chain check sprockets for wear,
all seals. I would suggest having the shop balance the engine: con rods,
5) Is there a "general rebuild FAQ" I can download? I don't want to miss
Kevin Sullivan -- 1960 MGA
Nichols Research Corp.
Shalimar FL USA